Multiple-die machine



H. H. BUNKER.

MULTIPLE DIE MACHINE. APPL'lcATloN man oEc.31 1921.

Patented Dec. 12, 1922.

ATTORNEYS Patented lflec. l2, 1922.

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ATENTl OFFICE.

HERBERT II. BUNKER, OF JERSEY CITY, NEW JERSEY, ASSIG'NOB TO KERLOW STEEL FLOORING CO., OF JERSEY CITY, NEW JERSEY, A CORPORATION 0F NEW JERSEY.`

MunrrrLn-nrn MACHINE.

Application tiled December 31, 1921. Serial No. 526,439.

To @ZZ whom t may concern.'

Be it known that I, HERBERT IFI. BUNKER, a citizen of the United States, residing in Jersey City, county of Hudson, and State of New Jersey, have invented certain new and useful Improvements in Multiple-Die Machines, of'which the following is a specification.

My invention relates to dies for bending or stamping a plurality of corrugations or bends in a work sheet or bar. The object of the present invention is to provide an improved device of the above class which shall be of simple construction and adapted to operate upon the work with less friction between the dies and work, less power required to operate the same, and less likelihood of unduly stretching the metal, and also to increase the life of the dies.

To these and other ends my invention consists in certain improvements and combination of parts as will be pointed out with greater particularity in the claims appended to this specification.

rlllie drawing shows a side view of my apparatus at the completion of a bending operation.

In the reciprocal multiple die type of bending machines in which the metal travels or creeps inward to supply the additional surface required to make the grooves and angles of tie mould, it has been found that when solid dies or those which cooperate with the full length of metal are used, that the friction between the dies and work is sufiicient to cause undue stretching and often rupture of the work. Since in such case the metal does not creep inward enough to prevent stretching, these old forms require enormous pressure to bend the metal into the several corrugations. One suggested means of avoiding the above difficulty has been to make at least one of the die members in several parts and have first one of these to operate upon the work, and then another and so on. But such an expedient requires a more elaborate construction than my present invention which 'achieves substantially the same result with a simpler construction and yet without likelihood of injury to the metal.

In the drawing the numerals 10 and 11 indicate a pair of die holders which are reciprocable toward and from each other and adapted when spread apart to have a straight work piece inserted therebetween. In the yment with any of the dies.

rnecessary 'by the bends or corrugations.

Duringthe first part ofthe bending opera-- tion the work piece 15 is in Contact with only a portion of the die membersgi. e., the edges 12a of the dies 12 are substantially the only parts of the dies which are in engagement with the work. For this reason the metal is subjected to less friction and is better able to'travel inward from each end of the machine. As the aws come together the edges 13a of the dies 13 and portions 18 of the holdn ers 10 and 11 also come into engagement with the work. It will be noticed however, that during no part of the'bending operation is the entire work strip in contact with the dies and even at the end of the operation it will be seen that the portions 17 of the work are unsupported or free from frictional engagey Thus my dies may in general be termed skeleton dies. In the embodiment of my invention which is illustrated, the portions 16 of the work `are the only parts which are clamped or cooperate on opposite sides with the dies.

For prolonging the life of the dies I have shown the members 12 and 13 as being secured by a bolt 14 or other appropriate means to enable'each of the dies 12 and 13 to be reversed to compensate for wear and prolong their life. The edge 13a of the die 13 is the portion of this die subjected to the most wear and when this die is shaped as illustrated I may subsequently reverse the die 13 and move the edge 13b into the position now occupied by the edge 13a, when the latter becomes worn, similarly the die 12 may be turned upside down to provide new edges 12b when the operative edges 12a becomeworn.

Among the advantages of my invention may be enumerated the freedom from friction caused by having portions of the work piece out of contact with the cooperating dies whereby the work is better enabled to i ing and rupture.

travelor creep inward and less power is required to operate the dies with a consequent lessened liability to undue stretch- Having portions of the work always out of contact with any of the dies enables a simpliied construction to be obtained at a reduced cost. During the latter part of the bending operation when the portion 16 of the work which was first of an arcuate shape and is subsequently flattened as shown,y there seems to be ay slight movement of the `metal in a direction diierent 'from its movement during the most part of the bending operation and in my invention this later back lash or slight movement reerred to is better taken care of and compensated for with less strain upon the jaws due to the unsupported portions 17 of the work. rilhe simplicity vof construction in which all parts of the dies subjected to wear may be reversible or easily removableis anv additional feature worthy of notice.

'My dies are adapted to produce a precise and predetermined form for the finished work7 and in the embodiment illustrated the machine is adapted after the bending t0 pro-duce a stamping operation; that is, one in which there is a slight tlow or movement of some of the particles of the metal work strip.

I claim:

l. A multiple skeleton die bending and stamping machine adapted to simultaneously form a plurality of corrugations in a work strip and comprising a plurality of relatively reciprocable holding members, attached to each or said holding members being a plurality or' dies over which the work is adapted to be shaped, said holding members on movement toward each other being adapted to first draw the work strip Within the machine from both ends in bending over the dies and then on further movement of the holding members to stamp portions of the work strip in a number of places,

other portions `of the' Work within the machine being o-ut'of contact with said dies.

2. multiple skeleton die bending machine adapted to sin'iultaneously form a plurality ot corrugations in a work strip and comprising a pair of reciprocableholding members, att-ached to each of' said reciprocable holdinff members being a plurality of dies over which the work is adapted to be shaped, said holding members on movement toward each other being adapted to irst draw the work strip within the machine in bending over the dies, the dies of one holding member being adapted on further movement of the holding members to (fo-operate with opposite portions of the other holding member to ciamp the Workbetween them to insure a predetermined form of the work strip while a portion or the work strip within the machine is Vout of contact with said dies and holc'ling members.

A multiple skeleton die bending machine adapted to simultaneously v'form a number of corrugations "in a metal work strip and comprising a plurality of relatively reciprocable holding members, a plurality ot' dies being attached to the holding members and over which the work is adapted to be drawn Within the machine in bending, both of said holding members being provided with a plurality oit major dies and anumber of auxiliary dies, a pair of said auxiliary dies on one holding member being arranged to co-operate with a major die on the opposite holding member to produce a stamping operation and sharp angled bends on further movement of the holding members toward each other, the work strip being out of contact with said dies and holding members in a number ot' places within the machine.

ln testimony whereof, l have affixed my signature to this specification.

HERBERT H. summa. 

